Demand for secondary batteries as an energy source has been significantly increased as technology development and demand with respect to mobile devices have increased. Among these secondary batteries, lithium secondary batteries having high energy density, high operating potential, long cycle life, and low self-discharging rate have been commercialized and widely used.
A lithium secondary battery is generally composed of a positive electrode comprising a positive electrode active material, a negative electrode comprising a negative electrode active material, a separator, and an electrolyte, and is a secondary battery in which charge and discharge is performed by intercalation-deintercalation of lithium ions. Since lithium secondary batteries may have high energy density, large electromotive force, and high capacity, the lithium secondary batteries are used in various areas.
Metal foil, such as aluminum and copper, are respectively coated with the positive electrode active material and the negative electrode active material, and the positive electrode and the negative electrode of the lithium secondary battery may then be prepared by rolling the coated metal foils. However, with respect to an electrode plate subjected to a post processing after a current collector, such as a aluminum foil or copper foil, is coated with an active material, since a phenomenon may occur in which the active material is exfoliated from the metal foil, swelling may occur and output characteristics and lifetime characteristics may be reduced.
As a measure to overcome the limitations, there have been attempts to prevent the above-described exfoliation phenomenon by processing the metal foil into a mesh and coating the mesh-processed metal foil with the active material.
However, with respect to the mesh-processed metal foil, there have been process problems in which, when the mesh-processed metal foil is coated with a slurry comprising the active material, the slurry flows down through the mesh.
Thus, there is a need to develop a new technique which may address the above-described process problems while using the mesh-processed metal foil as a current collector of the lithium secondary battery.